The present invention relates to a process and apparatus for the utilization of the sensible heat of hot coke from a coking installation during the dry cooling of the coke preheating of moist coking coal, wherein a flue gas received from a coke oven battery is led in succession through the coke cooling plant and then through the coal preheating plant, in direct contact with the hot coke and moist coking coal, respectively.
British Pat. No. 1,334,373 discloses a system for employing the sensible heat of hot coke produced in a coking operation for the drying and/or preheating of coal. An inert gas is cycled through the hot coke and the coal, and the inert gas may form a portion of the combustion products of the fuel gases that are used for the coking operation. It is necessary to pretreat the heat carrier gas fed to the coke cooling plant by removal of oxygen therefrom, and also to pretreat the heat carrier gas which is passed to the coal preheating plant. In the operation of the British system it is necessary to provide a dust separator and a compression arrangement.
German DT-OS No. 24 15 758 discloses an installation combined with a coke dry quenching plant and employed for the continuous drying and preheating of coal while utilizing heat which is transferred from the hot coke to a mixed gas. There is provided a combined quenching gas cycle and drying gas passage, and the combined system includes a device for treating the gas after the drying operation to condense therefrom steam which is released during the drying operation, with there also being provided an after-combustion chamber. This known installation employs the gases produced in the combustion chamber as the heat carrier gas which is circulated in a completely closed cycle. Thus, the heat carrier gas must in this manner by continuously replenished and added to the cycle. This known installation also of necessity includes very spacious components such as dust removers, blowers, injection condensers, heat exchangers and an after-combustion chamber for burning water-gas components from the quenching operation. Accordingly, this known installation is very expensive both with regard to manufacture cost and operating cost.
German DT-OS No. 24 34 827 discloses a process for recovering energy during a gas generation process, for example a coal gasifying or coal coking operation, for the purpose of drying or preheating the starting material, in particular fine coal employed for the coking operation. This known process achieves drying and preheating of the starting material by means of waste heat obtained during the cooling of the solid residues of the process, for example during the dry quenching of coke from a coking plant. More particularly, a primary closed gas cycle derives heat from the cooling of the hot coke, and such primary closed cycle of necessity is equipped with a dust separator. Heat is transferred from this primary closed cycle to a heat transfer and drying agent such as an inert gas, for example nitrogen, a flue gas of a coke oven, or a flue gas obtained from the combustion of a waste gas. The heat transfer and drying agent is maintained in a secondary closed gas cycle which also of necessity includes a dust separator. Due to the fact that this known process employs two separate cycles, such process is expensive with regard to manufacturing cost, inasmuch as it requires numerous expensive components, such as heat exchangers, dust separators and blowers.